With the constant development of the TFT (Thin Film Transistor) liquid crystal display technology, the TFT display device based on LTPS (Low Temperature Poly-silicon) skill possessing properties of low power consumption, high resolution, fast response speed and high aperture ratio has already become the mainstream, and widely applied in kinds of electronic apparatuses, like being applied in the digital electronic apparatuses, such as liquid crystal television, smart phone, tablet and digital camera.
However, the mobile display technology has been developed for higher quality, the finer degree, thinner body and lower power consumption. As the resolution gets higher and higher, the aperture ratio of the product becomes smaller. Meanwhile, the storage capacitor Cst (constructed by the pixel electrode, the common electrode and the passivation layer sandwiched therebetween) of the pixel gradually gets small, the charge duration of each pixel also gradually decreases. In the condition of prior art, for satisfying the requirement of optical quality and the transmission rate, it is difficult to make change to the thickness of the storage capacitor Cst and the area of the pixel electrode. Under such condition, the volume of the traditional storage capacitor Cst almost cannot be raised. The electrical quantity of each storage capacitor cannot maintain the normal working voltage of the pixel, and results in the issues of the cross talk and the Image Sticking, which tremendously lower the qualities of the array substrate and the display panel.